Fuel delivery systems typically include a fuel pump for delivering fuel under pressure from a fuel tank to an internal combustion engine. A check valve is usually positioned in line between the fuel pump and the engine to prevent back flow of fuel from the engine to the fuel pump when the fuel pump is deactivated. Fuel pressure is thereby maintained at the engine, resulting in reduced start-up time and improved starting of the engine. As depicted in FIG. 8, a conventional check valve apparatus 112 includes a screw-machined brass valve seat 144 and brass poppet valve 142 that has a rubber tip 143 molded thereto for sealing against the valve seat 144.
Unfortunately, however, the conventional check valve apparatus has several shortcomings. First, the screw machining process required to make the valve seat and poppet valve is particularly time-consuming and costly. Second, brass is a relatively heavy and costly material. Third, the process used to mold the rubber tip to the poppet valve is relatively expensive. Fourth, in fuel systems where fuel pump speed adjusts to engine fuel demand, a valve assembly having a brass poppet valve has relatively low responsiveness to rapidly changing fuel pressure and demand conditions such as when a vehicle is accelerating, decelerating, or shifting gears, because of the relatively high mass of a brass poppet valve.